And now we know that the hydrogen Honda will have an EPA-rated range that trumps both of the others.

Honda announced this morning that the 2017 Clarity Fuel Cell will be rated at 366 miles of range, although it does not appear that Honda has specified how many kilograms of hydrogen is stored onboard at 10,000 psi.

That far outstrips the Mirai's 312 miles, let alone the 265 miles of the Tucson Fuel Cell. It is also higher than the range rating of any electric car sold in the U.S.

Fuel-cell cars depend on the existence of a network of hydrogen fueling stations to make them viable.

So far, only certain regions of California have such sites, though plans have been announced to open hydrogen stations along certain corridors in the Northeast by 2020.

The Honda Clarity, meanwhile, will be offered not only with hydrogen fuel-cell power but also in battery-electric and plug-in hybrid versions—providing the first real-world market test of consumer preferences among alternative powertrains.